5V 1-Channel Solid-State Relay Module – Low Trigger
75.00 EGP
The 5V 1-Channel Solid-State Relay Module allows Arduino, ESP32, Raspberry Pi, and other controllers to switch AC loads silently. It features an active-low control input, optically isolated triac output, zero-cross switching, status LED, and a maximum rated resistive load of 2A at 100–240VAC. Designed for AC loads only.
5V 1-Channel Solid-State Relay Module
The 1-Channel Solid-State Relay is a compact electronic switching module designed to control AC-powered equipment using a low-voltage microcontroller signal. It operates from a 5V DC supply and uses an active-low input, which means the AC output switches on when the CH1 control terminal is pulled low.
Unlike a conventional electromagnetic relay, this module contains no moving contacts. Instead, it uses an optically isolated phototriac and a semiconductor output stage. Therefore, switching is silent and does not produce the mechanical clicking normally associated with standard relay modules.
Active-Low Trigger Operation
The control side contains three connections: DC+, DC−, and CH1. Connect DC+ to a regulated 5V supply and DC− to ground. Pulling CH1 close to ground activates the relay, while applying a high logic level or leaving the input inactive switches the output off.
This low-level trigger design can be controlled using Arduino, ESP32, Raspberry Pi, STM32, and other development boards. However, the module must receive a stable 5V supply even when the control signal comes from a 3.3V microcontroller.
The controller ground and module DC− terminal must be connected together for correct signal operation.
AC Solid-State Output
The output stage is designed for AC loads between approximately 100V and 240V AC at 50Hz or 60Hz. The maximum stated load current is 2A for a suitable resistive load under proper operating conditions.
The module uses zero-cross switching. Consequently, it switches the AC output near the zero-voltage point of the waveform, helping reduce electrical noise and switching stress.
Because the output uses a triac, this module must not be used to switch DC loads. A DC supply may remain conducting after activation because it does not provide the zero crossing required for the triac to switch off.
Advantages of the SSR Module
The 1-Channel Solid-State Relay provides silent operation, rapid switching, long service life, and resistance to vibration. Moreover, the onboard status LED makes it easier to monitor the control signal during testing.
It is useful for switching lamps, resistive heaters, small AC appliances, and other compatible AC loads. Nevertheless, motors, transformers, pumps, and incandescent lamps can draw a high starting current. For these loads, choose a relay with a significantly higher rating and verify the actual inrush current.
Key Features
- One-channel solid-state relay module
- 5V DC control-side power
- Active-low trigger input
- G3MB-202P-style SSR
- Optically isolated phototriac switching
- Zero-cross AC output
- Rated for 100–240VAC loads
- Maximum 2A resistive load
- Silent switching without mechanical contacts
- Fast operation and long switching life
- Onboard channel-status indicator
- Screw terminals for input and output wiring
- Compatible with common microcontroller boards
- Compact size for embedded control systems
Wiring Summary
- DC+: Regulated 5V DC supply
- DC−: Power ground
- CH1: Active-low control input
- AC Output Terminals: Connect in series with the AC live wire and the load
Safety Information
The output side may carry dangerous mains voltage. Disconnect all power before wiring the module. Install it inside a properly insulated enclosure and use an external fuse selected for the connected load.
Do not touch the module while it is connected to mains electricity. In addition, do not exceed the rated voltage or current, and do not use the module with DC loads.
Technical Specifications
| Specification | Details |
|---|---|
| Module Type | Solid-State Relay Module |
| Number of Channels | 1 |
| SSR Type | G3MB-202P-style |
| Control-Side Supply | 5V DC |
| Trigger Type | Active Low |
| ON Trigger Level | Approximately 0–1.5V |
| OFF Level | Approximately 2.5–5V |
| Trigger Current | Approximately 2mA |
| Output Type | Triac AC output |
| Load Voltage | 100–240VAC |
| AC Frequency | 50/60Hz |
| Maximum Load | 2A resistive |
| Switching Type | Zero Cross |
| Isolation | Phototriac optical isolation |
| Status Indicator | LED |
| Dimensions | Approximately 34 × 25 × 22mm |
| DC Load Support | No |
Suitable Loads
- Resistive heaters within rating
- Small AC lamps
- Compatible low-current AC equipment
- Temperature-control systems
- Home-automation projects
- Microcontroller-controlled AC switching
Loads Requiring Extra Caution
- AC motors
- Water pumps
- Transformers
- Compressors
- Incandescent or halogen lamps
- Equipment with high startup current
